As pilsner-type beers, beers having bitterness values exceeding 30 BU have been marketed outside Japan, but beers of from 20 BU to less than 30 BU are mostly found in Japan. In addition, in the beer markets in Japan of the recent years, bitter taste is likely to be avoided, and studies have been made on fermented malt beverages having various tastes while reducing bitterness.
For example, Patent Publication 1 reports a method including bringing a hop into contact with wort at a relatively low temperature, and gradually raising the temperature to boil, thereby controlling the quality of the bitterness ingredient of the hop added to give mildness and body of a post-aged hop-like hop. The patent publication describes that the beer obtained by the above method preferably has a bitterness unit B.U. of from 24 to 28.